#10: Java can't talk to the serial and parallel ports

• A standard extension to Java 1.2.

• Available on Mac, Windows, and some Unixes (Solaris).

• It's a very low-level API. There are no content or protocol handlers as there are with the URL classes. It's even lower level than the Socket classes. You just send and receive raw bytes to and from the port. You're reponsible for speaking HPCL or the Hayes AT command set or whatever protocol you need to speak.

• Only serial and parallel ports are supported. USB, Firewire, etc. are still needed.

import javax.comm.*;
import java.util.*;
import java.io.*;


public class PortTyper {

  public static void main(String[] args) {

    if (args.length < 1) {
      System.out.println("Usage: java PortTyper portName");
      return;
    }

    try {    
      CommPortIdentifier com = 
       CommPortIdentifier.getPortIdentifier(args[0]);
      CommPort thePort  = com.open("PortOpener", 10);
      CopyThread input = 
       new CopyThread(System.in, thePort.getOutputStream());
      CopyThread output = 
       new CopyThread(thePort.getInputStream(), System.out);
      input.start();
      output.start();

    }
    catch (Exception e) {
      System.out.println(e);
    }

  }

}

class CopyThread extends Thread {

  InputStream theInput;
  OutputStream theOutput;

  CopyThread(InputStream in) {
    this(in, System.out);
  }

  CopyThread(OutputStream out) {
    this(System.in, out);
  }

  CopyThread(InputStream in, OutputStream out) {
    theInput = in;
    theOutput = out;
  }

  public void run() {

    try {
      byte[] buffer = new byte[256];
      while (true) {
        int bytesRead = theInput.read(buffer);
        if (bytesRead == -1) break;
        theOutput.write(buffer, 0, bytesRead);
      }
    }
    catch (IOException e) {
      System.err.println(e);
    }

  }

}

• USB
• Firewire
• SCSI